Mis-handling or mis-understanding?
There is an old joke about the difference between an experienced Airbus pilot, and those of lesser experience and it goes like this:
An in-experienced Airbus pilot exclaims "What's it doing now?!!"
An experienced Airbus pilot calmly says "Oh, it's doing THAT again!"
IMHO the error here was that the F/O, assuming an autoflight malfunction, did not take full manual control, and got lost in the limbo that exists between partial autoflight and full control by the PF or the AP. "Mode mis-match" it was called in the early days.
An airmanship issue could be argued that, having experienced difficulty with what one thought the automation was doing, the climb could have been delayed and the aircraft returned to straight and level. My point is either YOU fly it or you let it fly you.
I remember once in the cruise at about F360, scanning around the displays, I happenned to catch both engines winding back (commanded by the autothrust) to idle. I immediately brought this to my F/O's attention and said words to the effect of "Hey, check this out!!"
We were in clear skies, no change of wind or temperature, no turbulence and both engines were running. I guarded the throttles, ready to push them forward of the climb detent, which overides autothrust. The airspeed decreased nearly to Vmin, when the engines roared back to climb power, stabilised @ the desired mach no and no further incident. It's an airbus - plastic heap of Euro****te.
Bottom line is for newbies on that thing-that-isn't-an aircraft, if it don't do what you want it to; 3 clicks! Auotpilot off, FD off, Autothrust off and then you're in a Cessna 150. Alpha prot and TOGA lock are the aeroplane trying to avoid a stall - and that can only be brought about by mis-handling, deliberate or not.
Hope this helps, cheers Ned.